Page 401 - Flexible Robotics in Medicine

394 Chapter 17

Figure 17.4
Comparison of the robotic system with and without triangulation. (A) The robotic system without
triangulation. (B) The robotic system with triangulation.

Wire 1 and Wire 4 are controlled by force, while wire 2 and wire 3 are controlled by
position. When wire 2 and wire 3 are released, the arm is straight as the initial state, as
shown in Fig. 17.3A and B because of the tension of wire 1 and wire 4. In this case, the
arm can be driven to pass through the channel of the endoscopic platform. When wire 2 and
wire 3 are pulled, a triangulation is formed through the adduction of module 1 and 2 and
the abduction of module 3. The triangulation for the arm of the manipulator makes it easier
to perform tasks in cooperation compared with the parallelly arranged arm without
triangulation. The arms of the manipulators gain more space to operate dexterously without
collision. The working area of the whole robotic system is enlarged due to the reduced
overlapping workspace of each manipulator. Fig. 17.4 shows the robotic system with and
without triangulation.

Module 5 is fixed to the endoscopic platform before the operation. Two nickel-titanium
(Ni-Ti) rods with flexible tubes are to drive the motion of the arm along its axial direction.
The end of the Ni-Ti rods are attached to the module 4, and the flexible tubes are connected